1. Field of the Invention
The present invention relates to the field of broadcasting. More particularly, the present invention relates to computer control of broadcasts.
2. Art Background
When broadcast technology was in its infancy, the process of scheduling of broadcasts and control of the equipment to generate the broadcasts were quite simple and typically were done manually. However, as broadcast systems have become more sophisticated, the problem of managing broadcasts and scheduling events which form broadcasts have become quite significant.
Regarding management of broadcasts, the technology today provides broadcast events (e.g. programs) from a variety of sources. For example, feeds may originate from a satellite receiver, from a videotape, from a television camera, from an internal line from a computer, etc. The same event broadcast in two different time zones may use a live feed from a satellite for a broadcast in one time zone and a videotape of the earlier live feed for a later broadcast in a second time zone.
Scheduling of broadcasts have become complex too. The organization and broadcast of commercials during programming typically have many broadcast constraints that must be followed. Some events are of unknown duration, making it extremely difficult to program subsequent to that event. Some events are programmed in parallel with other events, the operator of the broadcast, at time of broadcast, deciding which event to broadcast.
In addition, the management of live broadcasts have become complex. This type of program, such as a news program, is difficult to schedule in advance as the timing of information received, the amount of time taken for different portions of the broadcast and the broadcast resources change. For example, the duration of lead ins provided by the news anchor can vary. The live feed showing the news reporter at the story location may not be available. The importance of certain stories may change. To address such issues, a news program director will have story segments of varying lengths available and will typically dynamically modify the news broadcast based on the various timing requirements and known available resources.
Therefore, it is desirable to have a multiple channel shared resource, broadcast capability that handles various activities such as editing, news and commercial insertion, including live events, definition of schedule patterns that apply across several channels, mapping output channels to different uplink channels at different times, and integration of digital data and control with the uplinked video signals.
Computer controlled equipment is already an integral element in today's broadcast industry. Automation systems provide frame-accurate control of equipment; non-linear editors assemble material without the restrictions of tape-based linear systems; traffic systems deal with the complexities of scheduling commercial and spot play; computer graphics systems create new video effects and illustrations; news systems edit scripts, tie them to clips, and provide searchable archives.
However, the increasing prevalence of these independently designed computer-based systems does not automatically guarantee the smooth integration of these systems into a coherent, unified broadcast operation. To the contrary, these systems typically cannot "talk" to each other without creation of specialized "gateways" which attempt to perform a translation between systems. A customer's only alternative to this problem is to purchase "single-vendor" systems which require the user to discard their investments in pre-existing systems and use equipment that does not always meet all of their needs.
Compounding this problem is the need for enhanced capabilities while maintaining a simple operational structure. For example, it is desirable to generalize programming, e.g., of particular commercial breaks, such that they can be used a number of times, varying the commercials that form the break. Prior art structures, e.g., Open Media Framework Interchange (OMFI), created by AVID Technologies, provides a unified data structure which maintains as a combined entity the programming and the material used to implement the programming.
In addition, the broadcast industry generally uses simple time-based techniques for specifying the order of events, such as program events, commercials, run-downs and edit lists. These techniques define some combination of exact or approximate values for the start and duration of each event, and typically add some constraints, such as auto-follow, hard start or manual trigger. The list is then sorted by time. Ripple rules, complex, specialized rules which adjust start times of subsequent events based on the change of start time or duration of an event, are applied to adjust the timing of events when needed.
While this approach works satisfactorily when the start or duration of each event are known, the increasing prevalence of untimed or live events place difficult burdens on the definition of timing and the processing of complex ripple rules for any such system. The term origination refers to when video transmission begins at the facility. Multi-channel origination occurs, for example, when the signal representative of video to be broadcast comes from a tape, a disk drive, or be a live event being shot at the facility. Turnaround is used when the video signal originates somewhere else, is brought into the facility and immediately re-transmitted. Multichannel origination also complicates the definition of a broadcast. Furthermore, non-linear, disk-based playout, which refers to the current technology of disk drives which have both sufficient capacity and sufficient bandwidth to support the recording and real time playback of video, also causes problems as it is not sequential or linear as any frame of video can be directly accessed much as an individual record in a computer database. Thus significant problems can occur, particularly when there are live events with no duration and when there are subsequent events the start times of which cannot be changed. These systems fail to capture the basic time independent ordering constraints among the set of events to be defined for a broadcast or portion of a broadcast.